Electrical contact assembly



Oct. 24, 1950 R. E. H. CARPENTER ELECTRICAL CONTACT ASSEMBLY 4Sheets-Sheet 1 Filed Feb. 27, 1946 Inventor MW A Harney Oct. 24, 1950 R.E. H. CARPENTER 2,526,804

ELECTRICAL CONTACT ASSEMBLY Filed Feb. 27, 1946 v 4 Sheets-Sheet 2 Altorney Oct. 24, 1950 R. E. H. CARPENTER ELECTRICAL CONTACT ASSEMBLYFiled Feb. 27, 1946 4 Sheets-Sheet '3 A [lor/ley 0d- 24 1950v R. E. H.CARPENTER A2,526,804

ELECTRICAL comcm Asslzmsuf- Filed Feb. 27, 1946 v 4 sagas-shan 4 F/GQQ.

B WV I Attorney Patented ct. 24, 1950 ELECTRICAL CONTACT ASSEMBLY RupertEvan Howard Carpenter, South Croydon, England Applioation'February 27,1946, Serial No. 650,617 In Great Britain March 6, 1945 Il Claims.

This invention relates to the mounting of electrical contacts and itschief object is to secure the simultaneous opening or closing or both oftwo or more pairs of electrical contacts, such as those used inpolarised or other relays. The invention is particularly suitable foruse in relays having a pair of moving contacts which alternativelyengage one or other of two pairs of contacts which can be regarded asrelatively fixed contacts and which therefore effect the same operationas a double pole change-over switch. The invention, however, is alsoapplicable to other relays with multiple contacts, such as, for example,those required to open or close a number of circuits simultaneously.

According to the presen-t invention, one of each pair of co-operatingcontacts is so mounted that movement imparted to the one contact of apair upon closing of the contacts results or tends to result in amovement in the opposite sense of another contact of the same kind, orof more than one such contact in the apparatus, and the relativeposition of these moved contacts is then maintained frictionally.

For clearness of description, any two contacts which are brought into orout of engagement, such as the movable armature contact and a sidecontact of a polarised relay, will be referred to respectively as anactive and a passive contact. Thus, on the iirst operation of thedevice, after setting up, one passive contact will normally be reachedby its co-operating active contact earlier than the other or others, andconsequently this co-operating pair of contacts will close rst, The

motion thus imparted to that passive contact,

however, causes the other passive contact of a pair, or the otherpassive contacts to move towards their corresponding active contacts,and this motionl will only cease in each case on the meeting of eachpair of active and passive contacts. Then all thev passive contacts willbe aligned with respect to their co-operating active contacts, and allpairs of active and passive contacts will be pressed together withapproximately the same force, On the active contacts, which are allassumed to move together, being moved in the opposite direction, allpairs of active and passive contacts tend to separate at the sameinstant of time. Moreover, since the relative positions of the passivecontacts are maintained by friction, the second and succeeding closuresof the contacts will be nearly simultaneous also, and the pressuresbetween the passive contacts and the (3o-operating active contacts willremain equalised which is a state ofailairs which can 2 not beattainedby independent mounting of the individual contacts on springs.

In order that the invention may be readily understood and easily carriedinto effect, some forms of the invention will now be described withreference to the accompanying drawings, in which:

Figure l is a front elevation of a polarised telegraph type of relay towhich the invention is applied;

Figure 2 is a plan of the same;

Figure 3 is a rear elevation;

Figure 4 is a vertical section to an enlarged scale taken on the lineIV-IV in Figure r2; and

Figure 5 is an enlarged perspective view ofthe contact arrangements withthe passive contacts spread from the armature which bears the activecontacts;

Figure 6 is a perspective View of a modied arrangement in which theinvention is applied to the mounting of four passive contacts;

Figure 7 is an elevation looking on the face of a mounting for threepassive contacts.

Figure 8 is a View in elevation of the left terminal pillar of a form ofrelay using a contact supporting bar formed of insulating material, theinsulating bar and certain other parts being shown in vertical section;

Figure 9 is a view to the'right of Figure 8 with the armature removed;and

Figure 10 is a perspective view of Figure 8 with the armature removed.

Referring to Figures 1 to 5, the contacts are those of a double polechange-over or double` throw relay which is a polarised relay having themagnetic circuits and the mounting of the armature arranged as inapplicants U. S. Patent 2,412,123. The coil for the reversals current'S,the magnets ll, I2, the magnetic limbs 2, 3, the pole pieces 6, 1, thearmature l0, and the armature mounting springs 25, correspond to thesame parts in the said Patent 2,412,123, in which those parts aresimilarly numbered. Near one end the armature I0 carries a pair ofcontacts 30, 3l which project from its two opposite iiat faces; theyare-insulated from one another, and as best seen in Figure 5, areconnected by angle strips 32 33 and iiexible connector strips 32a and33a to terminal strips or tags 34, 35, which are mounted on the frame ofthe instrument. It can be seen that the contacts 30, 3l are spaced ashort distance apart and are placed side by side so that they areequidistant from the pivotal axis of the armature Ill. These form.. theactive contacts and they engage a pair of side contacts 36, 31 when theupper end of the armature moves to the left, as seen in Figure 1, andthey engage a pair of contacts 38, 39 when the upper end of the armaturemoves to the right in Figure 1. The pair of passive contacts 36, 31, or38, 39 on each side are mounted near opposite ends of a short bar 40, 4|of rigid insulating material, and pivoted at its centre about a verticalaxis which is therefore parallel to the contact bearing faces of thearmature I0. The pivotal arrangement is shown in Figure 4 where one ofthe bars 40 has a pin 42 forced into a vertical bore in the bar 40, andpasses through holes in tongues 43, 44 secured to the sheet metal pieces45 to engage frictionally the upper and lower surfaces of the bar 40. Acoiled compression spring 46 is introduced around the pin 42 between itshead 41 and the lower tongue 44. Thus, as the pin 42 is tight in the bar40, this spring forces the bar 40 down into contact with the ton-gue 44,and while the bar 40 and the pin 42 can turn about the vertical axis ofthe pin, friction is exerted by the tongue 44 to hold the bar 4Q in anyangular position into which it may be pushed.

The sheet metal pieces 45 are in eiTect flat springs riveted at theirlower ends to contact suD- porting plates 48, and at their upper ends at49, rubbing on the top edges of the plates 48, thereby providingcompliant members with damping means for vibrations of the armature inaccordance with applicants U. S. Patent No. 2,219,222.

The plates 48 are resiliently mounted at their lower ends on tags 58 andthe adjustment of the passive contacts 36, 38 is effected by resilientlyspringing the plates 48 inwards from the pillars 5|. For that purpose,the plates 4S are engaged by the points of the adjustment screws 52.

The passive contacts 36, 31, and 38, 38 are, therefore, mounted so thatthey can move through small angles about the axes of the pins 42, butthis angular movement is controlled by the friction between the bars 40,4| and the tongues 44. These contacts 36 and 31 or 38 and 39, aremounted with the members of each pair spaced apart by the same distanceas the active contacts 30, 3| so as to co-operate with the latter.

In an alternative construction the hars 40, 4| may be made of insulatingmaterial with metal foils on opposite faces, and the contacts 36 and 31or 38 and 39 connected each to one of the foils so that connection maybe made to them through the frictional joints between the bar 40 or 4|and the tongues 43, 44 which would then be insulated from one another.This alternative construction is illustrated in Figures 8 to 10 and willbe described iny greater detail hereinafter, arrangement the bar 40 or4| constitutes a rocker bar bearing contacts 36, 31 or 38, 38, which ifone of a pair moves, the other is caused to move in the opposite senseso that when the passive contacts, for example, 36, 31, are engaged bythe armature or active contacts 38, 3|, the passive contacts areself-aligned with respect to the active contacts.

The connections to the contacts 36, 31, and 38, 3S are made by flexibleinsulated wires 53 which on either side of the armature are taken downthrough short lengths of insulating sleeving 54 and are secured toterminal tags 55 which are carried in the same insulating mounting asthe tags 50.

In Figure 6, an arrangement is shown where there are four passivecontacts 55 mounted in pairs on separate rocker bars 51 which in thisinstance are shown to be vertical. The bars 51 are gripped in springfingers 5S through which hori- In either zontal pivot pins 59 pass, thepins 59 being xed in the bars 51. The rocker bars 51 can yield in thespring ngers 58 and turn through small angles about the pivot pins 59 sothat the passive contacts 56 of each pair simultaneously move inopposite senses. The spring iingers 58 are formed in two pairs eachconstituted by a loop of spring metal such as copper beryllium, andthese loops are secured to a horizontal rocker bar 40 which correspondsexactly to the bar 40 in Figures l to 5. In this case, however, therocker bar 40 is gripped by the spring fingers of a sheet metal loop 60through which a pin 6| fixed in the rocker bar 40 passes, so that as in.Figures 1 to 5, the rocker bar 40 can turn about the vertical axis ofthe pin 6|. The rocker bar 40 is mounted at the upper end of a plate 48which corresponds to the supporting plate 48 in Figures 1 to 5, andexcept that the armature must have four contacts, the rest of the relaymay be constructed as in Figures l to 5 and consequently functions as afour-pole changeover relay.

In Figure '7, a triple pole arrangement is illustrated, the passivecontacts 62 being mounted at the corners of an equilateral triangle onthe face of a cylindrical member 53 of insulating material mountedparallel to the contact carrying face of the armature of the relay andwhich is made hollow with an annular wall for the sake of lightness. Thedisc 63 is adjustably gripped by the points of two screws 64 which passthrough a gimbal ring 65 which can yield slightly, The screws 64 arethreaded in nuts 66 welded to the inside of the ring 65, and the screwsare provided with lock nuts 61. The gimbal ring 65 is also engaged bythe points of pivots 68 which project outwardly from the arms of aforked bracket 69. This bracket may be a continuation of a plate such asthe plate 48 in Figures 1 to 5, or may be xed to the upper end of such aplate. The pivots 68 are not in themselves adjustable, but thefrictional action of them can be adjusted by adjustment of the screws 64because the adjustment of the screws 64 slightly distorts the gimbal lring 65 and modies the frictional engagement of the pivots 68 with thatring.

Figures 8 to 10 illustrate the alternative construction referred toabove in which the bar for supporting the passive contacts is formed ofinsulating material. In this arrangement, the bar |48 (corresponding tothe bar 40 in Figures 1 to 5) is formed of insulating material and isprovided with sheet metal pieces |56 and |51 on the upper and lowerfaces. These metal sheets have extensions |58 and |59 bent against theiront face of the bar |40 and are connected to the passive terminals |36and |31, respectively. The frictional joint for supporting the bar andfor effecting electrical connections to the passive contacts are formedby pivot pins |60 and |6| supported in horizontal portions of tongues|43 and |44 which are insulated from one another. The pointed ends ofpivot screws |60 and |6| are seated in bearing sockets formed in metalsheets |56 and |51 so that the bar |40 can turn on the pivots under thefriction due to the pressure of the adjustable pivot screw |60. Thebracket |43 is resiliently supported on a terminal strip |50 and thecontacts are set, as in the case of Figures 1 to 5, by the screw |52threaded in the upper end of pillar' |5| and bearing on the bracket |43.The bracket |44 has a flexible connection to a terminal strip |55 sothat connection to the contacts |36 and |31 is completed through thepivotal joints and the pins |60 and |6|, The bracket |44 is supportedfrom the bracket |43 byrmeans of a screw |62 passing through clearanceholes in the brackets and in insulating washers or spacer disks |63.

In the above examples, the equalising system has been described asapplied to the passive contacts, but clearly the roles of the active andpassive contacts in this connection may be reversed; however, it isusually preferable to avoid the extra mass involved in such means on themoving parts.

It will be appreciated that the friction provided for maintain-ing theadjustable contacts in the adjusted position should be as great aspossible subject to the fact that the adjustment must occur under thesmallest operating forces exerted by the moving contacts. Any connectingwires from the contacts must be suiciently exible to ensure that theadjustable contacts will not be prevented from remaining in theposition. in which they are set. The adjustable contacts and the rockerbar or other member carrying them should have a minimum moment ofinertia and if mounted with compliance and provided with damping meansaccording to my U. S. Patent 2,219,222 dated October 22, 1940, should beas light as possible. It will also be apparent that an outstandingadvantage of the invention is that a single adjusting means only need beused for advancing and retracting all the adjustable contacts which willusually be the passive contacts; thus, the adjustment of such a relay orother apparatus is rendered no more difficult than that of anapparatushaving a single side contact on each side of the armature.

I claim:

1. A mounting assembly for electrical contacts, comprising two pairs ofcontacts vmounted for relative movement to permit of opening and closingof said contacts, a rocker member carrying one of said pairs of contactsand pivotally mounted about an axis to permit of movement of thecontacts carried thereby in opposite senses to and from the respectivecontacts of said other pair, frictional means engaging said rockermember to maintain same and the contacts carried thereby in positionsdetermined by the engagement of said two pairs of contacts, and a pairof conductive mounting means carried on opposite sides of said rockermember, said pair of mounting means being insulated from each other andforming the pivotal mounting for said rocker member for connecting thecontacts on said rocker member with a pair of xed terminals.

2. In a double-throw switch, the combination of an armature mounted tomove between two positions, a pair of active contacts carried by saidarmature on one side thereof, a second pair of active contacts carriedby said armature on the opposite side thereof, two pairs of passivecontacts arranged on opposite sides of said armature and in positions tobe engaged respectively by said pairs of active contacts carried by saidarmature, a rocker member arranged on one side of said armature andcarrying in insulated relation the contacts of one pair of said pairs ofcontacts and being adjustable in position by engagement with thecooperating pair of contacts, frictional means operative to maintainsaid rocker member in adjusted position, a second rocker member arrangedon the opposite side of said armature and carrying in insulated relationthe contacts of another pair of contacts and being adjustable inposition by engagement with the cooperating pair of contacts, frictionalmeans to maintain the second rocker member in adjusted position, a pairof metallic pivotal joints pivotally supporting each rocker member andbeing insulated from each other, a pair of xed terminals for each rockermember, and means forming separate connections from the contacts on eachrocker member through said joints to the respective fixed terminals.

3. A contact assembly according to claim 1 wherein said rocker member isformed of insulating material.

4. A switch according to claim 2 wherein said rocker members are formedof insulating material.

RUPERT EVAN HOWARD CARPENTER.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Kight Jan. 25, 1944

